• Journal of the Korean Institute of Gas
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• v.24 no.3
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• pp.54-62
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• 2020

Watching the leakage accident of the Gumi Hube Global AHF(Anhydrous fluoric Acid), I experienced how much chemical accidents affect on our society. Since then, many studies have been conducted on chemical accident in many fields. The use department wanted to find improvement plans for the process system and apply them to the field. The safety field wanted to study improvement of safety through the analysis of damage effects and apply them to emergency response to reduce damage effects. In this study, Mechanical safe devices have been applied which can respond quickly to chemical accidents occurring during the charging operation to enhance the safety of the AFH ISO Tank(Anhydrous fluoric Acid International Organization for Standardization Tank). Investigation of similar tanks confirmed that other chlorine tanks with the same working procedure as AHF ISO Tank have a mechanical safety device, EFV(Excess Flow Valve). Applicability and performance for emergency shutdown when EFV is introduced in AHF ISO Tank can be verified by comparing and examining the accident situation of Hube Global Accident and the accident in Ulsan 2018. Comparing accident cases, expected performance and applicability, It is suggested that EFV, a mechanical safety device that can reduce damage from chemical accidents to the tank and handle accidents early, should be introduced to the tank.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.382-390
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• 2017

In this paper, we consider particular exposure scenarios to evaluate human effects for inductive commercial wireless charging device operating at low frequency. The coil used in this study is the A10 model in Qi standard proposed by WPC(Wireless Power Consortium), and input power is 5 W to the operating frequency of 155 kHz. In perfectly aligned condition, the max leakage magnetic field is $257.58{\mu}T$ which is obtained at the side of the device, and it is exceeded about 7.4 times of the ICNIRP 1998 reference level. The SAR is evaluated with homogeneous phantom which has electric constants of wet skin. The max value of the SAR is $134.47{\mu}W/kg$ which is obtained at the side of the device also, and it is much lower than the international guidelines. Especially, it showed higher SAR values in case of misalignment condition, so we will need to consider the misalignment condition importantly when we evaluate human effects for wireless power transfer system.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.68-73
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• 2013

In this paper, we proposed a readout circuit of pulse waveform and rate for a U-health system to monitor health condition. For long-time operation without replacing or charging a battery, either pulse waveform or pulse rate is selected as the output data of the proposed readout circuit according to health condition of a user. The proposed readout circuit consists of a simple digital logic discriminator and a dual-mode ADC which operates in the ADC mode or in the count mode. Firstly, the readout circuit counts pulse rate for 4 seconds in the count mode using the dual-mode ADC. Health condition is examined after the counted pulse rate is accumulated for 1 minute in the discriminator. If the pulse rate is out of the preset normal range, the dual-mode ADC operates in the ADC mode where pulse waveform is converted into 10-bit digital data with the sampling frequency of 1 kHz. These data are stored in a buffer and transmitted by 620 kbps to an external monitor through a RF transmitter. The data transmission period of the RF transmitter depends on the operation mode. It is generally 1 minute in the normal situation or 1 ms in the emergency situation. The proposed readout circuit was designed with $0.11{\mu}m$ process technology. The chip area is $460{\times}800{\mu}m^2$. According to measurement, the power consumption is $161.8{\mu}W$ in the count mode and $507.3{\mu}W$ in the ADC mode with the operating voltage of 1 V.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.79-84
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• 2007

In this paper, the finite element analysis of a valve screw for a LPG cylinder has been presented on the leakage safety and strength one, which are computed and investigated by a contact normal stress and von Mises stress between a female screw of a valve and a male screw of a neck ring in a LPG bombe. The LP gas charging pressure of a LPG bombe is $8{\sim}9kg/cm^2$, which is pressurized to the screw sealing contact areas between a valve and a LP gas cylinder. The peak failures of the screw tooth height due to a scratch wear and chipping loss of the contact area may decrease screw tooth strength and increase a leakage of a LP gas. These are strongly affect to the contact normal and von Mises stresses of the valve screws. The FEM computed results show that the tooth height loss due to a wear and chipping failure of the screw peak does not affect to the LP gas leak and strength of a valve screw theoretically. But if the tooth wear of the screw height of a brass valve overpasses the critical strength safety of the valve, the valve screw may be failed in fastening the valve and a LP gas bombe suddenly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.36-42
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• 2019

Europe and North America are paying attention to residential ESS(Energy Storage System) that can manage energy efficiently. The ESS is a system that stores and manages the electric power by charging and discharging the battery. The ESS is generally used in conjunction with photovoltaic systems. The ESS supplies the load of the power generation time and stores the remaining PV power to supply the load at the non-power generation time. However, due to the high price of residential ESS, low electric rates and increasing block rates, there is no market of residential ESS in Korea. This paper reviews the price condition and the capacity for applying PV and residential ESS to household of apartments using HOMER in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.52-59
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• 2020

Currently, the domestic electricity rates for houses are charged by applying a progressive level according to monthly electricity usage. Electricity rates rise sharply wWhen the amount of electricity used is large, electricity rates rise sharply. The standardized electricity rate progressive system has limitations in that it lacks consideration of the consumers' power usage patterns and limits consumers' their options. Accordingly, the Ministry of Trade, Industry and Energy and the Korea Electric Power Corporation have been demonstrating the basis of a rate system for housing, which is a method of charging electricity according to the amount of electricity used by season and time. In this paper, 10 electricity usage patterns were derived through from AMI data analysis for 5 five years of 362 apartment complexes located in metropolitan cities. The patterns were, and then applied to the existing domestic electricity rate and time-by-time rates applied to demonstrations, and by time-by-time rates in the US and Australia. The effect of the optional rate by pattern was compared and analyzed. As a result, it was confirmed that benefits occurred in five5 patterns compared to existing rate plans, and the electricity rates increased in 5 five patterns, and t. This phenomenon shows the same phenomenon withis the same as the overseas rates, including domestic rates being demonstrated.

• Science of Emotion and Sensibility
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• v.23 no.2
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• pp.51-60
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• 2020

This study aimed to develop a modular smart clothing system for heart rate monitoring that reduces the inconvenience caused by battery charging and the large size of measurement devices. The heart rate monitoring system was modularized into a temporary device and a continuous device to enable heart rate monitoring depending on the requirement. The temporary device with near-field communication (NFC) and heart rate sensors was developed as a clothing attachment type that enables heart rate monitoring via smart phone tagging when required. The continuous device is based on Bluetooth Low Energy (BLE) communication and batteries and was developed to enable continuous heart rate measurement via a direct connection to the temporary device. Furthermore, the temporary device was configured to connect with a textile electrode made of a silver-based knitted fabric designed to be located below the pectoralis major muscle for heart rate measurement. Considering the user-experience factors, key functions, and the ease of use, we developed an application to automatically log through smart phone tagging to improve usability. To evaluate the accuracy of the heart rate measurement, we recorded the heart rate of 10 healthy male subjects with a modular smart clothing system and compared the results with the heart rate values measured by the Polar RS800. Consequently, the average heart rate value measured by the temporary system was 85.37, while that measured by the reference device was 87.03, corresponding to an accuracy of 96.73%. No significant difference was found in comparison with the reference device (T value = -1.892, p = .091). Similarly, the average heart rate measured by the continuous system was 86.00, while that measured by the reference device was 86.97, corresponding to an accuracy of 97.16%. No significant difference was found in terms of the heart rate value between the two signals (T value = 1.089, p = .304). The significance of this study is to develop and validate a modular clothing system that can measure heart rates according to the purpose of the user. The developed modular smart clothing system for heart rate monitoring enables dual product planning by reducing the price increase due to unnecessary functions.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.93-102
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• 2016

Vehicle-to-Grid (V2G) system, bi-direction power trading technology, enables drivers possessing electric vehicle to sell the spare electricity charged in the vehicle to power distribution company. The drivers gain profit by charging electricity in the day time of high electricity rate. In this regard, the government is preparing the policies of building and supporting V2G infrastructure and demanding the potential consumers' preference for the V2G system. This paper attempts to analyze the consumers' preference using the data from obtained a survey of randomly selected 1,000 individuals. To this end, choice experiment, an economic technique, is employed here. The attributes considered in the study are residual amount of electricity, electricity trading hours, required plug-in time, and price measured as an amount additional to current gasoline vehicle price. The multinomial logit model, which requires the assumption of 'independence of irrelevant alternatives', is applied but the assumption could not be satisfied in our data. Thus, we finally utilized nested logit model which does not require the assumption. All the parameter estimates in the utility function are statistically significant at the 10% level. The estimation results show that the marginal willingness to pay (MWTP) for one hour increase in electricity trading hours is estimated to be KRW 1,601,057. On the other hand, a one percent reduction in residual amount of electricity and one hour reduction in required plug-in time in V2G system are computed to be KRW -91,911 and -470,619, respectively. The findings can provide policy makers with useful information for decision-making about introducing and managing V2G system.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.41-53
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• 1999

The rate of automobile ownerships has been increased significantly in multi-family housing sites so that government has made new parking regulations increasing the rate of parking supply by the high demand of parking lots in multi-family housing sites. However, the new regulation of parking supply has several problems that it applies to only new multi-family housing sites and disregards to the locational distinctions around the sites. It also has reduced to the open spaces in the sites and increased the price of housing units especially to the small size units of multi-family housing sites by increasing the number of underground parking lots. Furthermore, the residents have not been equal opportunity to access their parking lots even though they have been charged to equal amount of financial burden for the construction of underground parking lots. This research aims to relieve above problems by analysing parking supply and demand management strategies both domestic and foreign countries, and suggest to new parking management system for multi-family housing sites in 21st Centuries. This research reveals that most of multi-family housing sites want to be applied 1) diverse parking supply regulations considering the locational distinctions of sites, 2) parking lot ownership programs, 3) charging parking fees to second vehicles, 4) increasing parking lots both in the sites and around the sites, 5) enforcing police power to the parking violation vehicles to their sites. Especially, the multi-family housing sites consisting of small & medium size of units and locating in small & medium size of cites strongly want to be accepted new Parking regulations considered their locational and social distinctions and applied police power to the parking violation vehicles in their sites compared to the other multi-family housing sites.

• Science of Emotion and Sensibility
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• v.14 no.3
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• pp.435-444
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• 2011

The development of ubiquitous healthcare technology and portable electronic devices requires new energy sources for providing continuous power supply. This study particularly focuses on an energy harvesting system capable of charging energy using clothing. One of the sources for energy harvesting is heat energy, which is the difference in temperature of the body and the surrounding environment. In this study, the skin temperature distribution of the human body was empirically measured to determine the basic materials needed to develop heat energy harvesting clothing. The distribution of skin temperature in different sections of the human body was analyzed. The analysis found that the skin temperature of the upper body was higher than that of the lower body. The area close to the heart with a lot of blood flow was especially high. The skin temperature of the back side of the body, such as the back of the neck, upper back, and waist, was higher than that of the front side of the body. As for the arms, the skin temperature of the upper arms was higher than that of the lower arms, and the skin temperature of the back side of the arms was lower than that of the front and the flank side of the arms. The difference in the average skin temperature and the environment temperature was highest at the back of the neck, and thereby is considered to be the most appropriate section to integrate the heat energy harvesting function and structure. The following sections had the next highest difference in values, listed in descending order: the back of the waist, the sides of shoulders, the front chest area, the front side of the upper arms, and the front abdomen. Based on the skin temperatures of the different sections of the human body, this study outlines the basic guidelines for developing heat energy harvesting clothing.